Project Summary/Abstract Adolescent alcohol use is significant risk factor for the development of alcohol use disorders or other psychiatric disorders later in life, however the molecular changes that mediate this are largely unknown. Previous studies suggest that epigenetic reprogramming in the adult amygdala due to adolescent alcohol exposure may be responsible for adult psychopathology. It has been shown that enhancer of zeste homolog 2 (EZH2), which is a major component of the polycomb repressive complex 2, is important in brain maturation. Additionally, preliminary data from both rodent models of adolescent alcohol exposure and human postmortem amygdala, suggest that EZH2 may be an important regulator of epigenetic changes that occur after adolescent alcohol exposure. However, its role in epigenetic reprogramming at a candidate gene or whole genome level or its role in regulating anxiety and increased drinking in adulthood after adolescent alcohol exposure is unknown. This proposal will evaluate the role of EZH2 through a number of different approaches including brain region- specific pharmacological and genetic intervention, and whole-genome sequencing approaches to determine the role of EZH2 in mediating molecular, epigenetic, synaptic, and behavioral changes that occur after adolescent alcohol exposure. EZH2 will be characterized in different subregions of the amygdala using immunohistochemical and fluorescent in situ hybridization after adolescent alcohol exposure. Pharmacological and genetic inhibition will be used to determine if inhibition of EZH2 in the central nucleus of amygdala (CeA) attenuates anxiety-like behavior and higher alcohol consumption caused by adolescent alcohol exposure, and subsequent molecular and anatomical (spine density) outputs in adulthood. Chromatin immunoprecipitation sequencing will be used to analyze changes in EZH2 occupancy throughout the whole genome and identify novel gene hubs and gene network pathways that are disrupted by EZH2 after adolescent alcohol exposure. These results will determine the tractability of EZH2 as a novel therapeutic intervention for the use in alcohol use disorders in individuals who began drinking during adolescence.